用扩散界面相场模型研究陶瓷烧结过程中五球模型内部的气孔扩散与演化过程。采用一组随时间和空间连续变化的取向场变量和浓度场变量来表征烧结过程微结构特征,用Ginzburg—Laudau动力学方程和Cahn—Hilliard动力学方程分别描述取向场变量和浓度场变量随时间的演化。结果表明,陶瓷烧结过程中,颗粒间的气孔通过晶界向较大的气孔扩散聚集,颗粒内部的气孔则通过晶粒基体内部向颗粒间的空隙和颗粒外部空间扩散。陶瓷颗粒的气孔通过晶界或基体扩散到晶粒外部空间的过程,就是陶瓷坯体烧结的致密化过程。
The evolution and diffusion of pore in sintering, locating in opening space among grains and inside grains, were studied using phase-field method. The mierostructure during sintering was described by a set of spatially continuous and time-dependent field variables. The evolution kinetics of orientation field variables and density field variables were described by Ginzburg-Laudau equations and Cahn-Hilliard equations, respectively. The simulation results show that small pores locating among the grains diffused and assembled to Big pores through grain boundaries and the pore locating inside grains diffused through matrix of grains. These results were well consistent with the experimental results and theoretical results of other simulations.